


Uninvited Guest

by twyly56



Category: Shadowhunters (TV), The Shadowhunter Chronicles - All Media Types
Genre: BAMF Isabelle Lightwood, BAMF Jonathan, Bad Parent Valentine Morgenstern, Breaking and Entering, But He Doesn't Understand What He is Feeling, But His Reactions to Things Can Get a Bit Extreme, Canon-Typical Violence, Caring Jonathan, Confused Jonathan, Couch Cuddles, Courtesy of Living in a Hell Dimension For Ten Years Straight, Good Jonathan Christopher Morgenstern | Sebastian Verlac, Hurt Isabelle Lightwood, Jonathan Doesn't Know How He Feels About Jace, Jonathan Has No Clue How to Behave in Polite Society, Jonathan Has a Crush on Izzy, Jonathan Wants to Get to Know Clary, Jonathan's Really Not That Bad, Jonathan's a Bit Like a Kid For Certain Things, Mentions of the Magnus Bane & Valentine Morgenstern Body Swap, Mirrors, New York Shadowhunter Institute, Protective Jonathan Christopher Morgenstern, Recovering Isabelle Lightwood, References to Addiction, So He's a Confused Cookie, Socks, Sweet Jonathan, Tea, They're Brothers... But Not, Whipped Cream, Yin Fen Detox, glamours
Language: English
Status: In-Progress
Published: 2018-12-30
Updated: 2018-12-30
Packaged: 2019-09-30 11:05:52
Rating: Teen And Up Audiences
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 2
Words: 2,622
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/17222846
Author URL: https://archiveofourown.org/users/twyly56/pseuds/twyly56
Summary: Isabelle is rescued from Azazel by a blonde man who calls himself Jonathan. He takes her to a safe place to detox, and he is really an odd person. He doesn't give her bad vibes, per say. He was just odd.





	1. Chapter 1

Jonathan grabbed the first blonde guy walking on a New York sidewalk he found that looked to be roughly his age and height, knocked him out with a hastily thrown burst of demonic power, and hogtied him to a chair, so he could memorize his features and create a glamour that could pass around other people. Lilith knows that one that looked like his father wouldn't work for shit. The damn bastard was bald as hell with dark facial hair, and Jonathan remembered that he used to be blonde. He had had blonde hair and green eyes. Just like the guy he had found. 

Though, honestly, almost anything was better than looking like a burnt demonic freak. The pain didn't really bother him anymore, but his reflection was just _hideous._  

The young man had these black runes on his neck, forearms, and chest that he discovered after he removed his clothing. Jonathan vaguely remembered what they meant, but it was all a bit fuzzy in his head. He hadn't thought about it in years. Jonathan came back to the guy he had tied to the chair in order to let him go, but the man just started screaming his head off. He wasn't really sure why. I mean, he was wearing the glamour now, so why was the guy so freaked out? Melodramatic British Nephilim. 

"Calm down! Stop screaming," Jonathan said. 

"Let me go! I don't have anything that could be of value to you. Please!" the blonde yelled at him. Or maybe he was begging. 

Meh. 

In any case, it was loud and grated on his ears. Jonathan _hated screaming._ He had done and heard more than his fair share of screaming in Edom. Why, oh  _why_ couldn't he just have a single conversation that didn't end with raised voices? 

The demon blooded boy sighed, crossing his arms over his chest with a little huff. 

"Calm down! I'm not going to hurt you! I just wanted to borrow your face. I'll put on a different one once I find it, okay?" Jonathan said. "I am going to let you go. Despite what everyone seems to think, I don't actually kill everything I come across." 

The man kept screaming at him, a mixture of obscenities and some other words that he just sort of tuned out after a few minutes. Jonathan sighed again and pressed his thumb into the pressure point on the blonde's neck. The man shuddered, and he slipped into unconsciousness, going limp in the chair. 

"You know, I did try to be patient with you. But I do _really_ hate screaming," Jonathan told the unconscious man. He patted him on the head. 

Jonathan untied him after taking all his weapons and his outer clothes and shoes. It wasn't that cold outside anyway, and he needed it more than him. Jonathan dumped the guy on a blue bench under a sign that said 'bus stop'. Whatever the heck that was. Mundanes were so weird. 

 

Isabelle stumbled down the darkened alleyway. The only source of light was the one from the street lamps at the mouth of the alley behind her. Every part of her body hurt terribly. Her legs, her back, her head. Her hands ached worst of all, pain lancing through them as they trembled uncontrollably. She didn’t really know where she was or where she was going. Truthfully, at this point she didn’t care. All that mattered was the vampire den she knew was somewhere around here. Wherever the hell here was.

Isabelle's red rimmed eyes landed on the rusty looking door, and she stepped towards it on shaky legs. Her hands balled into fists as she pounded on the door. There was no response, and she couldn't hear anyone inside. But that didn't mean there was no one there. The cool wind whipped at her hair, blowing it into her face. Isabelle exhaled, trembling with need. She craved yin fen so badly. She _needed_ it. Needed it like she needed to breathe air. She pounded the door again, desperate, so desperate. 

"Open up! I know there are vampires here," Isabelle called. She hit the door again. "Open up... _please._ " 

She stepped back from the door, panting. Her eyes shut briefly as she tilted her head back, trying to regain her focus. Everything just hurt. Her brain was all muddled. A gasp escaped her lips when hands clamped down on her shoulders, and she was spun around. The man wearing a dark business suit slammed her against the wall of the building. His face flickered, turning demonic for a split second. Her eyes widened. 

"I could smell your weakness a realm away," the demon said. 

"What do you want from me?" Isabelle asked. 

"The Mortal Cup. Please," the demon replied. He smiled sweetly at her, and his hand wrapped around the ruby pendant around her neck. He roughly yanked it off, slipping it into his jacket. 

The back of her neck stung from the snapping of the chain. Isabelle glared up at him, and she punched him in the face. The demon didn't appear to be fazed. She swung at him again, and he moved out of the way. The demon cracked his knuckles, dark eyes staring at her coolly. Isabelle came at him, throwing blow after blow, but her punches lacked the power they usually did, her energy sapped from her desperate craving. She ached. The demon blocked her punches, and he ducked under one of them, easily catching her by her forearms and pulling her forward towards him. 

"Hey! Let the girl go!" a man on a bike riding past the alley yelled, stopping. 

"Hey!" a busboy coming out a restaurant said. 

The demon looked between the mundanes, and Isabelle struggled weakly against his grip. He released her after a moment of silence. Her eyes fell on his hands as he raised them up. A whitish smoke rose from his fingers, and the mundane men let out pained screams in unison. They fell to the floor, dead. Isabelle planted her palms on the demon's chest, and she shoved him away from her. Her breath came out in soft pants. Cold sweat beaded on her forehead. She trembled, blinking hard to clear her vision as it spotted. 

Damn it. Here she was, helpless as a maiden in one of those stupid fairytales, and she was going to die. Alone. 

There was a clatter at the end of the alley, and she glanced to see what it was this time. A figure with blonde hair sprinted down the cracked asphalt toward them. The demon swung at him, but the stranger flipped up into the air, twisting his body, and landed on his feet a few yards away from him. Bright green eyes flashed in the dim lighting of the street lamps. 

"Not you again," the demon snarled. It sounded almost like he was irritated. 

"Me," the stranger agreed. "Say hi to Mother for me, yeah?" 

The stranger lifted the blade in his hand and sliced at the demon. The demon dodged out of the way and tried to punch him. The stranger darted by Isabelle and kicked off of the wall of the alley, slashing his blade at the demon. There was an explosion of insects, and the demon dissipated. The stranger landed on his feet again, blade extended from his hand like it was a part of him. Isabelle stepped away from the wall she was by and cautiously moved toward him. The blonde tilted his head at her like he was surprised. 

"Are you okay?" he asked. 

"Who are you?" Isabelle asked him. 

The stranger slid his blade back into a sheath that was on his back, hidden under his black overcoat. 

"My name is Jonathan," he responded with a smile. "What's yours?" 

She saw a black rune creeping up the side of his neck from under his collar. 

"It's... Isabelle. Are you a Shadowhunter?" Isabelle asked. 

"Oh..." Jonathan looked thoughtful for a moment. "Yeah..." 

"I've never seen you around the Institute," Isabelle said. 

"Yeah, I'm not from around here," Jonathan told her. "But I love the city so far." 


	2. Chapter 2

Jonathan was honestly fascinated with Isabelle. He had never seen a yin fen junkie in person before. He supposed it was a good thing he had extensively learned about all things demonic during his time in Edom. He knew exactly how to help her detox, if she wanted to. And maybe the Shadowhunter girl would help him find his little sister once she was better. He did hope she would. Jonathan had had no luck thus far in his search for who his father had called Clarissa. He remembered she had red hair, like an open flame, and eyes as green as his used to be. The demons had tried their best to torture all the humanity out of him, but he just could not forget that tiny baby girl who had been his sister. 

She must be, what, seventeen? Eighteen, now? Or maybe nineteen even. Jonathan wasn't really sure how old he was. All he knew was that she was two years younger than him. Jonathan had to find her before their father did. He would only hurt her, and Jonathan's blood boiled at the very thought. No one should ever hurt his little sister. Really, the only real solution was to eliminate Father from the equation entirely, but he wasn't quite certain where the man was. So he instead focused his efforts on finding his sister. 

He had helped Isabelle into the apartment and onto the couch in the living room. Jonathan watched as the Shadowhunter girl rubbed at her temples, blinking slowly at him as she regained her coherence. He sat on the chair across from her with his legs crossed, elbows resting on his knees. Isabelle looked over at him with confusion in her brown eyes. He smiled in what he hoped was an assuring manner. 

"You know, jonesing for vampire venom is not exactly conducive to success when battling demons," Jonathan commented idly. He tapped his fingers on his jean clad thighs. 

"How did you know?" Isabelle asked. She stopped rubbing her head. 

"The darting eyes. The grey complexion. Not to mention the bloody wrist that you're nursing," Jonathan listed off. "That's probably the most obvious clue. Unless you like putting on a pair of fake fangs and biting your own wrist open in your spare time. And you use some sort of mundane drug regularly. Of course, you could have gotten attacked by a vampire, yes, but they don't usually tend to go for the wrist first." He waved his hand at her. "There is really not that many reasons for you to look like that. Process of elimination." 

Well, that, and he could smell the venom in her blood. But he wasn't going to tell her that. 

"I've never seen you around the Institute," Isabelle murmured absently. 

He smiled slightly and moved off the chair to the little side table. Jonathan plucked up a small brown bottle, and he carried it over to the Shadowhunter girl. 

"That's because I'm not from around here. Remember?" he reminded gently. 

"Where are you from?" Isabelle asked. 

"Idris," Jonathan replied. He unscrewed the cap from the bottle and held up the dropper of yellow fluid to her. "Here. One drop of this, and you'll feel like a new person." 

She held up her hand to stop him from bringing it closer, and she squinted at it suspiciously. 

"What is it?" Isabelle asked him. 

"It's expensive. Perfectly harmless, see?" Jonathan said. He dabbed his middle finger at the end of the dropper and brought the liquid to his mouth. He sucked it off. "It's from an extract of a root found in Neela Don. It's a quaint little town." Isabelle examined the little brown bottle, sniffing it. Jonathan knew it smelled rather earthy. "Look, it will help with the pain of your venom addiction. Speed up your recovery." The Shadowhunter girl set down the bottle slowly. He held out the dropper to her. "Come on." 

Jonathan released a drop of the yellow liquid onto her tongue, and she shuddered, eyes falling shut as she swallowed. He smiled at her. Isabelle sighed, sounding relieved, and he could sense her pain decreasing. She glanced at her own hands, holding them up. They didn't tremble and shake like they had earlier. She looked up at him in surprise. 

"It's not a miracle drug. In a few hours, it'll wear off, and you'll feel like shit again. But it does help," Jonathan told her. 

Isabelle nodded and brushed her wavy hair out of her face with a steady hand. 

"So why aren't you in Idris with your Institute?" she asked. 

"Oh, I haven't been to Idris in years, actually," Jonathan admitted. The Shadowhunter girl blinked at him. "I've been studying abroad... here and there. I had some... family issues. Let's just say Idris wasn't the best place for me to deal with them. I had to get away. So I took matters into my own hands and left. I found my way to New York, and well..." He gestured around himself. "Here I am." 

"You went AWOL?" Isabelle said. She raised a dark eyebrow. She sounded more curious than accusing. 

"I prefer to think of it as more of a mandatory leave of absence," Jonathan replied. He smiled. "The main thing is that it really did help me. And I can help you. If you want my help, that is." 

The Shadowhunter girl grabbed her jacket up from beside her on the couch, and she moved to stand up. She started moving towards the door. 

"Thank you so much, but I have to get going," Isabelle said. 

Jonathan stepped in front of her and held out his hand to stop her, careful to keep from actually touching her. She paused. 

"You walk out that door, and within an hour, you'll be back at a vampire den, begging for a bite," Jonathan told her. He crossed his arms over his chest. Isabelle met his eyes. "You need at least a day to get enough venom out of your system to be able to handle yourself." He gestured toward the door and stepped out of her way. "But if you want to leave, then by all means, go right ahead. I will not stop you." 

Isabelle looked at the door for a moment, silent, before she looked back at him. Jonathan smiled at her. 

"How do you know all of this? We never learned this at the Institute," Isabelle said. 

"Like I mentioned earlier, I studied abroad. I had a rather... _varied_ education. I mostly specialized in demonic lore and demonology. I know plenty about yin fen and its effects," Jonathan explained. His lips twisted wryly. "Probably more than most of the professors in Idris." He waved a hand at the couch. "Please sit. I'll go see if I can scrounge up something for you to drink. Do you like tea?" 

"Um... sure. That's fine," Isabelle answered. She set her jacket back down, and she returned to her spot on the couch. 

Jonathan walked over to the kitchen and set a pot full of water on the stove to boil. He got out his tea spices from the cabinet, placing it on the counter. He looked back at her. 

"I love tea. You can add so many things to it, and there is so many different types to try..." He made a happy noise when he found his honey jar. He plonked it on the counter beside his tea spices. "It's really great." 

Isabelle made a soft chuckle and shook her head. Jonathan grinned. 

"If you say so," Isabelle said. 


End file.
